Large-scale seed planting typically involves a tractor or other motorized vehicle which pulls a seed planter across a field. During each pass across the field, the seed planter operates to deposit seeds into a trough formed by a cooperating pair of slitters. After seeds are deposited in the trench, a trailing pair of press wheels operate to fill the trough with the soil which was removed by the slitters to form the trough.
Various seeder mechanisms have been developed to dispense seed in cooperation with a slitter assembly. Some mechanisms involve chutes or similar assemblies which deposit seeds onto a cone planter. The cone planter laterally distributes the seeds and feeds them in a controlled manner into an edge-receiving funnel. The seeds are gravity-fed and channeled by the funnel into the troughs formed by the slitter.
In certain environments it may be desired to meter the seeds in a controlled manner such that they are deposited in the soil at relatively fixed concentrations and distances. For instance, it may be desired to deposit seed clusters, each containing a relatively constant number of seeds, at fixed or predetermined distances from one another. Such a protocol is particularly desirable when planting multiple varieties of plants or when conducting controlled agricultural experiments.
A conventional method for accomplishing this objective involves the use of a cable spans the length of a plot to be seeded. The cable is staked into the ground at each end of the field and includes sphere-shaped knobs attached to the cable at a predetermined distance from each other. The seed planter that is pulled behind the tractor has a cable-follower device that contacts the cable and actuates a seed release device each time the cable-follower device moves over a knob on the cable. After each pass across the field, the operator relocates the cable by repositioning the stakes along the next path to be seeded. This conventional practice is time-consuming and is frequently unworkable depending on the dimensions of the field to be planted and the number of workers available to realign the cable for each pass across the field.
A seeding apparatus may include a control unit to meter a predetermined amount of seed at desired intervals of time, distance, or the like. For instance, in one embodiment a tractor-towable seeder may include a metering wheel, a sensor which detects the radial or circumferential travel of the wheel, and a control unit which receives the sensor input and triggers the release of seeds at the desired intervals. The control unit may include, for instance, a programmable logic controller or a low voltage relay and distribution network. Suitable sensors may be selected based on the desired metering apparatus and control device.
In certain embodiments, the metering wheel may provide improved accuracy in seed deposition at predetermined plot lengths, particularly during long seeding runs. In one preferred embodiment, the metering wheel has a fixed circumference which is an integral of the desired plot length a single trigger disposed on the circumference of the metering wheel such that a seed deposition apparatus is triggered once per rotation of the wheel, thereby optimizing accuracy and precision in measurement of the plot length.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.